November 30, 1939--The Soviet Union Invades Finland

On November 30, 1939, the Soviet Union invaded Finland, demanding that Finland cede some substantial border territories, claiming that Finland was security risk to Leningrad, the Soviet capitol, which was only approximately 20 miles from the Finnish border.

The Soviets expected a quick and easy victory. The entire population of Finland was less than the population of Leningrad. The invading Soviet army had three times as much infantry, a much more advanced airforce, and approximately 100 times more tanks. The Fins had almost no tanks, and had never trained in fighting them.

However, in the previous years, Stalin had purged his army of all officers who were not 100% loyal to him, and replacing them with less experienced yet more loyal soldiers. The Soviets tried to use blitzkrieg tactics, which failed miserably in the forests, swamps, lakes, and rivers of Finland. Also, the Fins had a great will to win. Though they couldn't blow up tanks with other tanks, soldiers could run up behind them and throw glass bottles of gasoline, with matches tied to them, into the tank's air ducts. Another advantage that the Fins had was that many of their roads, traveling through miles and miles of forest, were only one lane wide. Finnish soldiers divided the Soviet army by destroying tanks and armored cars at the front and back of sections of the army, trapping the troops in between.

When late December and Early January came around, Stalin wasn't happy. His army had been humiliated in utter failure. The Soviet Chief of Staff,  Boris Shaposhnikov,  was given full authority over the invasion, and he commanded the suspension any frontal assaults. Also, the commander of Soviet forces, Kliment Voroshilov, was replaced with  Semyon Timoshenko on January 7.

At this time, the primary focus of the invasion was switched to the Karelian Isthmus. The leaders reorganized their armies and changed tactics. They shipped the army massive amounts of new tanks, artillery, and other reinforcements.

The reinvigorated attack began with the Soviet's huge artillery barrage of the Finnish lines. After ten days, the Soviets finally broke through on the western Karelian Isthmus. On February 11, one day after the breakthrough, the Soviets deployed around 460,000 men, 3,350 artillery pieces, 3,000 tanks, and 1,300 aircraft on the Karelian Isthmus. Opposing them, the Fins had only 150,000 men.

After this the Finnish defenses crumbled and retreated rapidly. On February 15, commander-in-chief of Finnish forces, Carl Mannerheim, autharised a retreat of the 2nd corps, on the western Karelian Isthmus, to the Intermediate line. Meanwhile, the Fins on the eastern Karelian Isthmus continued to withstand Soviet attacks.

By this time, Finnish forces were nearing exhaustion. On the Soviet side, casualties were high, embarrassment threatened the Soviet regime, and there was a chance of intervention from France and Britain. The two nations began negotiating peace terms, but the Fins thought that they were too hard, and declined until Sweden, under threat of German attack, announced publicly that they would give no aid to Finland. By February 29, Finland agreed to negotiate with the Soviets, and the formal peace treaty was signed in Moscow on March 12.

Thus, the Winter War ended.

Sources: Winter War | Wikipedia, The Winter War of Finland and Russia | Youtube